/// <summary>
/// Extends BeginInvoke so that when a state object is not needed, null does not need to be passed.
/// <example>
/// progresschangedeventhandler.BeginInvoke(sender, e, callback);
/// </example>
/// </summary>
public static IAsyncResult BeginInvoke(this ProgressChangedEventHandler progresschangedeventhandler, Object sender, ProgressChangedEventArgs e, AsyncCallback callback)
{
if (progresschangedeventhandler == null)
{
throw new ArgumentNullException("progresschangedeventhandler");
}
return(progresschangedeventhandler.BeginInvoke(sender, e, callback, null));
}